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.TH PCAP-LINKTYPE 7 "6 April 2020"
.SH NAME
pcap-linktype \- link-layer header types supported by libpcap
.SH DESCRIPTION
For a live capture or ``savefile'', libpcap supplies, as the return
value of the
.BR pcap_datalink (3PCAP)
routine, a value that indicates the type of link-layer header at the
beginning of the packets it provides.  This is not necessarily the type
of link-layer header that the packets being captured have on the network
from which they're being captured; for example, packets from an IEEE
802.11 network might be provided by libpcap with Ethernet headers that
the network adapter or the network adapter driver generates from the
802.11 headers.  The names for those values begin with
.BR DLT_ ,
so they are sometimes called "DLT_ values".
.PP
The values stored in the link-layer header type field in the savefile
header are, in most but not all cases, the same as the values returned
by
.BR pcap_datalink ().
The names for those values begin with
.BR LINKTYPE_ .
.PP
The link-layer header types supported by libpcap are described at
https://www.tcpdump.org/linktypes.html .
.SH SEE ALSO
.BR pcap (3PCAP)
